Reading through the topics on Y Combinator, there seems to be renewed interest from people in learning Lisp, which is a language I've never heard of until recently. So I looked online for a primer on Lisp, to my surprise, I find Lisp similar to Prolog (in intent), which is something that I'm more familiar with, in relation to the AI classes that I took during my undergraduate studies.

But I was still curious why Prolog was hardly mentioned until I found this:

Q: How does Prolog differ from Lisp?

Lenat: There has been a constant dream in AI, by a large fraction of people in the field for 25 years, of the form: there really ought to be some way of formalizing and axiomatizing human thought and reason. But time and time again, all attempts at axiomatizing things have led people to trivialize them, to the point where they no longer apply to what they were originally modelled after in the real world.

There are a lot of people in the field who want to be sure, who want to believe that they can get absolutely precise, logically guaranteeable models that are close to what is going on in the real world. If you believe that, then the kinds of operations you want as primitives are logical operations, those involved simply in theorem proving. Those are the sort of operations that are present in Prolog.

Q: Why is Prolog used more in Europe than in the U.S.?

Lenat: In most European countries [and elsewhere- jb], you have very rigid hierarchies of 'ancient' professors, and then younger professors, and then research associates-- and then it filters down about seven levels to the people actually writing the programs. It is the people at the top who decide what research is going to get done, not the people at the bottom who have experience with what is actually happening.

The people at the top-- who [may] want to believe in a nice, simple, mathematical, axiomatizable universe-- basically determine the kind of research that is going to get done. The experiences that would lead them to change their minds are simply not occurring to them, they are occurring to the people at the bottom, who have no say.

That was just hilarious. I didn't realise that North America and the rest of the world hated each other so much when it comes to AI. Well, here's a more measured historical reference of why Lisp is used more commonly than Prolog in North America.